Reliability of (New) Supercritical Power Plants
Transcript of Reliability of (New) Supercritical Power Plants
J. Shingledecker, Ph.D. Sr. Project Manager, EPRI Fossil Materials & Repair Program (P87)
J. Philips, Ph.D., J. Wheeldon EPRI Fossil Fleet for Tomorrow Program (P66)
K. Coleman EPRI Boiler Life and Availability Program (P63)
“Advanced Technologies & Best Practices for Supercritical Thermal Power Plants.” Partnership to Advance Clean Energy – Deployment
(PACE-D) Technical Assistance Program (U.S. AID) November 21-22, 2013: New Delhi, India
Reliability of (New) Supercritical Power Plants U.S. Experience
2 © 2013 Electric Power Research Institute, Inc. All rights reserved.
Outline
• Historic Steam Temperatures U.S. • Early Supercritical (SC) Pulverized Coal (PC) Experience • Current Performance of U.S. SC Fleet • Recent U.S. SC/Ultrasupercritical Power Plants • Outlook for future
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1900 ’10 ’20 ’30 ’40 ’50 ’60 ’70 ’80 ’90 2000 ’10 Year
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pera
ture
, Deg
rees
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Tem
pera
ture
, Deg
rees
C
Eddystone 1
Philo 6
History of Steam Conditions for Fossil Fired Power Plants (U.S.)
• During 1st 60 years of the 20th century, steam turbine temperatures rose from 500°F to 1200°F – Thermal efficiency rose
from 4% to 40% (HHV) • Eddystone experienced
several materials issues – Derated from 1200°F to
1140°F • No significant improvements
in steam temperature for 50+ years
Maximum Steam Turbine Inlet Temperature History
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Initial SC Experience (Eddystone) led to reduced steam parameters – modest improvements have followed
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U.S. Fleet Efficiency (circa 2008)
SC-PC Powerplants have higher efficiency
Sub. Critical*(600-1600 psig)
Sub. Critical**(1800-2600 psig)
Super. Critical(3334+ psig)
20
30
40
Effi
cien
cy (%
) - U
.S. P
lant
s (2
008)
Average Efficiency (Bit) Average Efficiency (Subbit) 90th Percentile (Bit.) 90th Percentile (Subbit.)
* < 200MW** >200MWAdapted from: Improving the Efficiency of Coal-Fired Power Plants for
Near Term Greenhouse Gas Emissions Reductions, DOE/NETL-2010/1411
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Early Supercritical (SC) Experience (U.S.)
• Nomenclature: – EAF = Equivalent Availability Factor – EFOR = Equivalent Forced Outage Rate
• Factors affecting performance:
– 1960’s-70s aggressive goals (Eddystone) conservative designs
– Economic pressures operations and maintenance – Scale-up of unit sizes growing pains – Boiler designs: Pressurized draft balanced draft
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Improved Design Dramatically Improved SC Plant Availability
Adapted from: B. Slettehaugh et al. “Integrated Gasification Combined Cycle (IGCC) Versus Supercritical Pulverized Coal (PC) for Power Generation from Coal,” COAL-GEN 2005
1st Gen, 1st 5yrs
2nd Gen, Pressurized,
Pre-Conversion
2nd Gen, Pressurized,
Post-Converstion
2nd Gen, Balanced Draft
0
20
40
60
80P
erce
nt
Plant Description
EAF EFOR
Supercritical (SC) PC Plant Availability Improvements
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U.S. SC-PC Plants have the same availability today as subcritical plants
Adapted from: B. Slettehaugh et al. “Integrated Gasification Combined Cycle (IGCC) Versus Supercritical Pulverized Coal (PC) for Power Generation from Coal,” COAL-GEN 2005
EAF for PC Units Larger than 375 MW (5 year period ending 1999)
# of Units Mean Top 25% Subcritical (375-525MW)
90 81.8 >88.3
Supercritical (SC)
102 82.0 >85.9
*Based on NERC GADS Data
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Some Recent SC and USC PC Plants in Service in USA and Canada
Location Power Producer and Plant Name
Net output MW
Fuel Startup year
Main steam temperature,
ºF
Boiler vendor
Alberta, Edmonton EPCOR/TransAlta, Genesee Unit 3
450 Sub-bit 2005 1058 SC PC
Hitachi
Arkansas South West Electric Power, Turk Plant
600 PRB 2013 1112 USC PC
B&W
Colorado, Pueblo
Xcel Energy, Comanche Unit 3
750 PRB 2009 1055 SC PC
Alstom
Illinois, Lively Grove
Peabody Energy, Prairie State Energy Campus Units 1 and 2
2 x 750 Bit 2011/12 1055 SC PC
B&W
Iowa, Council Bluffs
MidAmerican, Walter Scott Unit 4
850 PRB 2007 1057 SC PC
Hitachi
Kentucky, near Louisville
LG&E-KU, Trimble County Unit 2
750 Bit. 2010 1082 SC PC
Doosan Babcock
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Some Recent SC and USC PC Plants in Service in USA and Canada
Location Power Producer and Plant Name
Net output MW
Fuel Startup year
Main steam temperature,
ºF
Boiler vendor
Missouri, Weston
Kansas City Power& Light, Iatan Unit 2
850 PRB 2010 1085 SC PC
Alstom
Texas, near Bremond
Luminant, Oak Grove Units 1 & 2
2 x 800 Lignite 2009 1055 SC PC
Alstom/B&W
West Virginia, near Morgantown
GenPower, Longview Plant
700 Bit 2011 1056 SC PC
Foster Wheeler
Wisconsin, Oak Creek
We Energies, Elm Road Units 1 and 2
2 x 600 Bit 2009/10 1055 SC PC
Hitachi
Wisconsin, Wausau
Wisconsin Public Service, Weston Unit 4
500 PRB 2008 1085 SC PC
B&W
Bit. is bituminous coal B&W is Babcock & Wilcox PRB is Powder River Basin sub-bituminous coal
PC is pulverized coal Sub bit is sub-bituminous coal SC is supercritical
USC is ultra-supercritical USC is defined arbitrarily as temperatures above 1100ºF
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In last 8 years: ~13GW of SC/USC PC plants have entered service in North America
30yr old mothballed
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Innovations for today’s SC-PCs
• Higher efficiencies through higher steam parameters – Higher strength and
corrosion resistant materials
• Environmental controls
Temperature has a greater effect compared to pressure for efficiency
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Early-life challenges in new SC/USC-PC Plants
Exfoliation Blockage
Creep-Strength Enhanced Ferritic (CSEF) Steel Erection and Fabrication
Metallic Wet FGD Corrosion
Stress Corrosion Cracking (SCC) in waterwall panels
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Some Recent (U.S.) Powerplants Utilizing Advanced Stainless Steels Location Power Producer and
Plant Name Net
output MW
Fuel Startup year
Main steam temperature, ºF
Boiler vendor
Advanced Stainless
Steels
Arkansas South West Electric Power, Turk Plant
600 PRB 2013 1112 USC PC B&W 347HFG
Colorado, Pueblo
Xcel Energy, Comanche Unit 3
750 PRB 2009 1055 SC PC Alstom Super 304H
Kentucky, near Louisville
E.ON USA, Trimble County Unit 2
750 Bit. 2010 1082 SC PC Doosan Babcock
310HCbN (HR3C)
Missouri
Kansas City Power& Light, Iatan Unit 2
850 PRB 2010 1085 SC PC Alstom Super 304H
Wisconsin, Oak Creek
We Energies, Elm Road Units 1 & 2
2 x 600
Bit 2009/10 1055 SC PC Hitachi 310HCbN (HR3C)
Wisconsin, Wausau
Wisconsin Public Service, Weston Unit 4
500 PRB 2008 1085 SC PC B&W 347HFG (replacement)
Bit. is bituminous coal B&W is Babcock & Wilcox PRB is Powder River Basin sub-bituminous coal
PC is pulverized coal Sub bit is sub-bituminous coal SC is supercritical
USC is ultra-supercritical USC is defined arbitrarily as temperatures above 1100ºF
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Damage has been observed from exfoliation of steam-grown oxides
347H superheater blocked by exfoliated oxides
Drain Line Erosion
Exfoliated Oxide Flakes
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Best practices can avoid or manage steam-grown oxide exfoliation
Rapid Inspection for Exfoliation with
LFET probe
Inner diameter shot-peening can be used to effectively eliminate
tube blockages from steam-grown oxides (EPRI Report 1024027)
As-received surface = oxidation & exfoliation
Peened surface =
thin adherent scales
650C – 17bar Steam
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Innovations in New USC Power Plants: AEP John W. Turk Unit 1
• Failures in Dissimilar Metal Welds (DMWs) have challenged the operation of SC powerplants
• EPRI Developed a new filler metal (EPRI P87) to eliminate the failure mechanisms in DMWs
• J.W. Turk has 4418 DMWs - 1215 have design temperatures of 1120- 1150°F (604-620°C)
• EPRI P87 was chosen for the most demanding temperature applications
347HFG-P87-T91 DMW Joint
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Proper Implementation of CSEF Steels (Gr. 91/92) is crucial to good SC/USC Performance
Poor Casting Quality
Improper Welding & Design
Specification Guidance that Goes
‘Beyond the Code”
User-Friendly Tools
Poor Field Heat-Treatment resulting in excessive oxidation
and overtempering
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Corrosion in Wet Flue Gas Desulfurization (FGD) Systems
Through-wall vessel leaks in 11months of operation (Duplex Alloy 2205)
Mitigation Options have been implemented on New Units: Potential
Adjustment Protection = no corrosion!
Corrosion in Immersion Zone
Forced Oxidation Wet FGD Schematic
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Cracking in T23 waterwall panels Similar issues in China and Europe (T24)
• High-restraint conditions: waterwalls, attachments, roof tubes
• Reheat cracking • Stress corrosion cracking:
– during commissioning – Significant number (~1000) of
failures, rework required • Hydrogen induced cracking
– Poor fabrication practice
Examples of Cracking observed early life in T23/24
EPRI Welding Guidelines & Current Research on SCC
includes best practices for T23
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Latest USC Power Plant in USA (2012) • SWEPCO’s (American Electric
Power) 665-MWg (630-MWnet) Turk Plant near Hope, Arkansas – PRB Coal – B&W Boiler/Alstom Turbine – 251bar/602°C/610°C (3640psia/1115°F/1130°F) – Projected Heat Rate: 8700 Btu/kWh (39.2% HHV)
• Materials: – SH/RH Tubes: 347H, 347HFG (shot peened) – Waterwall: T12 – Headers & Piping: Gr. 92 and 91
Source: AEP
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Project Milestones
• Project announced Aug 9, 2006 • Received permit to install Nov. 5, 2008 • EPC full notice to proceed Dec. 8, 2008 • First coal fire Oct. 27, 2012 • Initial generator synch Nov. 8, 2012 • Commercial Operation Dec. 20, 2012 • Performance Tests Feb. 11 -13, 2013
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U.S. SC/USC Plant Experience
• New materials are being utilized in SC/USC construction • ‘Early-life’ issues can be traced to improper use/selection of
materials • The experience and concurrent EPRI research can be used
to mitigate and/or eliminate these potential failure modes – Proper use of CSEF steels using EPRI guidelines – Proper selection of materials and alternatives for wet
FGDS – Proper fabrication and commissioning practices for
T23/24 – Procurement guidance for advanced stainless steels and
weld metals for dissimilar metal welds
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A final word
Sub. Critical*(600-1600 psig)
Sub. Critical**(1800-2600 psig)
Super. Critical(3334+ psig)
20
30
40
Effi
cien
cy (%
) - U
.S. P
lant
s
Average Efficiency (Bit) Average Efficiency (Subbit) 90th Percentile (Bit.) 90th Percentile (Subbit.) New Supercrtical Plants (est.)
* < 200MW** >200MW2008 data from: Improving the Efficiency of Coal-Fired Power Plants for
Near Term Greenhouse Gas Emissions Reductions, DOE/NETL-2010/1411
Estimated efficiency (HHV) for new U.S. SC/USC Plants
2-4% increase HHV = 5-10% Reduction in Fuel, emissions, etc.
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